Helicopter

You have to do the mission The calm before the storm. You have to follow the helicopter until it lands for the last time the go up on the train tracks the run or walk to the building that the helicopter landed on, then jump off of the track and land on the roof of the building that the helicopter is on then run, or walk over to it the jump over the wall, get into the helicopter, after you get it up into the air fly it underneth the stiars that you will take to get to the roof. It should look like this. C is the stairs, H is where to put the helicopter. Now it's time to go up the stairs enter the yellow spot and when they spot you you have to run and jump the wall and get into the helicopter.